Don't know anybody at TA, but can ask my contacts in France. However, TA may not have made steel cages in a while, and may not have the equipment any longer. So even 15,000 items may not be tempting.
As an aside - who would buy 15,000 bar-mounted cages? Maybe TA thought the request was an April fool's joke? Or is the true quantity 150?
Jan Heine, Seattle
P.S.: I have one or two of those bar-mounted TA cages (NOS) that I could sell. Interested parties contact me with offer off-list.